Housing for Sensor Interface Electronics

ABSTRACT

The invention is an improved housing for storage of an electronics interface package. The housing is attached to a sensor adaptor or connector, and rotatable about that sensor adaptor. The interface package is contained in the interior of the housing, and is orientatable in the interior to provide different angles of view.

This application claims the benefit of provisional application for patent Ser. No. 61/138,004 filed on Dec. 16, 2008, which is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

Many field processes use sensors located within the process environment, such as level sensors. These sensors are generally directly mounted in a tank or process line, or a portion of a sensor mounted to the outside of a tank that works in conjunction with a portion of the sensor in the tank (such as a magnetic level sensor that operates in conjunction with a magnetic float in the tank). The sensors are electrically connected to an electronic interface package which is stored in a housing to protect the electronics from the ambient environment. In a direct mount package, the sensor protrudes from the tank, and the housing mounts via a sensor adaptor or connector to the sensor. In other applications, a cable may be routed from the sensor through conduit to the housing holding the electronics. Power is generally provided to the housing as required for operation of the sensor and electronics. The housing may need to be mounted in a particular configuration, for instance, at the top of a process tank, at the bottom of a process tank, on the side of the process tank or offset from the process tank by a desired angle. See FIG. 11. Many sensor interface packages include components that provide manual interaction with the sensor at the housing, such as a visual indicator of the sensor readings (display screen or an alpha numeric display), or an input apparatus (such as a keypad or cable plug) to operate the sensor in manual mode, enter a calibration sequence, or invoke other functionality. When the sensor interface package includes such interactive components, the housing must be orientable to allow the user to access or view the interactive components. The most common manner to provide the needed degree of housing orientation is to have a separate housing model or construction for each needed orientation or installation. Shown in FIG. 11 is multiple orientations for the housing/sensor package, including sensor 100 (here a long probe), the housing 110, and a connector 120 between the housing and sensor. As shown in FIG. 11 a-j, multiple mounting configurations are possible, but many require a different housing model to provide for bottom mount, top mount, or left/right side mount. The manufacturer will typically assemble and ship the unit as a package (sensor/housing/connector) based upon the customer's ordered configuration, to keep the unit's inner electronics being unnecessarily disturbed by the customer.

The need to account for multiple mounting orientations requires that the manufacturer stock multiple models of the housing/adapter. Stocking multiple embodiments for the housing is inefficient. As can also be seen in FIG. 11, the housing 110 includes a view window 130 to allow an operator to view or operate the interactive components in the housing, such as a display. As can be seen, the orientation of that window 130 can be right-side up, upside down, left or right facing (e.g. sideways), depending on the mounting configuration. This makes viewing the display, for instance, difficult.

SUMMARY OF THE INVENTION

The invention is an improved housing for storage of an electronics interface package. The housing is attached to a sensor adaptor or connector, and rotatable about that sensor adaptor. The interface package is contained in the interior of the housing, and is orientatable in the interior to provide different angles of view.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the housing

FIG. 2 is a side cross section through the housing of FIG. 1. shows a cross section through one embodiment of the housing of the present invention.

FIG. 3 is a cross section through the housing, but a perspective of the corresponding connector.

FIG. 3 detail is a view of FIG. 3 showing an alternative embodiment.

FIG. 4A is a perspective view of the housing showing the interior of the module compartment with an L shaped member installed in the compartment.

FIG. 4B is a perspective view of the housing showing the interior of the module compartment with an electronic module holder installed in the compartment.

FIG. 5A is a side view of the electronic module holder.

FIG. 5B is a bottom view of the electronic module holder.

FIG. 6A is a perspective view of one embodiment of an electronic module top.

FIG. 6B is a bottom view of an electronic module base.

FIG. 6C is a perspective view of one embodiment of a module puller.

FIG. 7 is a cross section through the module compartment showing the installed components.

FIG. 8A is a perspective view of one embodiment of viewing glass cover for the module compartment.

FIG. 8B is a perspective view of one embodiment of a glass cover retainer ring

FIG. 8C is a cross section through one embodiment of a viewing glass cover for the interface electronic module compartment.

FIG. 9 is a perspective view of the interior of the terminal compartment.

FIG. 10 is a cartoon depicting movement of the wiring in the interface component.

FIG. 11 is a front view of several prior art mounting orientations of housing/sensor/connector.

DETAILED DESCRIPTION OF THE INVENTION

Shown in FIG. 1 is a prospective view of one embodiment of the housing. The housing body will generally be formed from cast stainless steel or aluminum, if used as an explosion proof housing, or it may be formed from a cast rigid plastic material that is non-reactive with the environment otherwise. As shown, the housing includes a body 1 that contains an interior that is partitioned into two compartments, an module compartment 10, and a terminal compartment 30. The two compartments are preferred but are not necessary. A single compartment could be used if the module compartment contained a terminal strip or a matching plug or socket to accommodate incoming wiring, sockets or plugs, or other cable connector.

As shown in FIG. 1, both compartments have an opening that may be closed with removable covers 11 and 31. As depicted in the housing cross section of FIG. 2, the module compartment 10 and terminal board compartment 30 are stacked, one above the other, with the two openings into the compartments orientated at an angle of about 75 degrees to each other. Other angles may be used depending of the specific housing design. A first channel 21 connects the two compartments, while a port 22 provides for entry into the module compartment. Terminal compartment 30 includes one or more ports 23 providing wiring access to the terminal compartment via attachable conduit to the port 23.

Removably mating with the housing 1 is a sensor connector 50 (shown in FIG. 3). As shown sensor adapter is hollow right angle tube that is threadable into port 22 in the housing. The sensor connector 50 may be a straight connector or a connector formed with any desired angle. The sensor will generally directly attach to the sensor connector at opening 53 (such as a sensor top threading into opening 53). Alternatively, a conduit may be attached to opening 53 and be routed to the sensor 100. In any event, wiring will operationally connect the sensor with equipment located in the housing (such as the module, later described). Located at the opposite end of the sensor connector 50 is an upstanding finger 51. As shown, upstanding finger 51 projects upwardly from the rim of the threads 50A. When the sensor adapter 50 is threaded into the port 22, the finger 51 projects into module compartment 10 or is adjacent the interior of the module compartment 10. The sensor connector 50 also has a slot 50.1 to accommodate a sealing ring, such as an “O” ring. A set screw may be used through housing 1 to contact and set the degree of rotation of the sensor connector 50 with respect to the housing 1. However, because the fit of the sensor connector 50 to the housing 1 is designed to be a tight fit, a set screw, clamp or other means to fix the position of the sensor connector may not be required.

As shown in FIG. 4, positioned on the bottom of the module compartment 10 are stops 13. Rotatably mounted to the bottom of the module compartment on cylinder 14 is “L” shaped stop bracket 15. Stop bracket 15 has a center opening to slide over cylinder 14. Stop bracket 15 may be retained in place on cylinder 14 with a snap ring or other suitable retaining device (such as the module mount next described). The end of the stop bracket 15 includes a projecting finger 15.1 that couples with finger 51. As shown, the stops 13 are angled to accommodate the movement of the stop bracket 15 and provide stops to the bracket at a desired angle of bracket movement or rotation. In use, the sensor connector 50 is first threaded into the housing 1 and the stop bracket 15 next installed. After installation of the stop bracket 15, the sensor connector 50 may rotate with respect to the housing 1 until finger 51 contacts finger 15.1, further rotation of sensor connector (or relatively, the housing) will rotate stop bracket 15 until bracket 15 contacts stop 13. In this fashion, the housing is allowed to rotate with respect to the sensor connector through a fixed angular range, here through a range slightly greater than 360 degrees. Alternatively, the interior wall of the port 22 may have a downwardly projecting insertable finger (e.g. snap inserted in a corresponding groove) that interfaces with a rotatable ring inserted into a circumferential groove in the interior of the sensor connector—the rotatable ring would have an upstanding finger that interfaces with the port finger, providing almost 360 degrees of relative rotation (not shown).

As described, the interaction of the sensor connector finger 51 with the bracket 15 and stops 13 creates a means to allow rotation of the sensor connector within a fixed range, here the range is slightly in excess of 360 degrees. The movable stop bracket allows a minimum of one full 360 degree rotation. Other means to allow rotation of the sensor connector with respect to the housing, within a fixed range, may be employed. For instance the sensor connector 50 may have a finger 50.3 projecting from the base of the connector adjacent the housing exterior (shown dashed in FIG. 3 detail). The exterior of the housing could have a slot into which a downwardly projecting finger 50.2 may be inserted and fixed (such as by a screw, or snap-in). This downwardly projecting finger or stop bracket would be inserted after assembly, and act as a stop to the upward projecting finger. In this fashion, the rotational motion of the assembled sensor connector/housing may rotate through a fixed range of about 360 degrees. The 360 degree rotation allows for great flexibility in setting the orientation of the housing/sensor for various mounting orientations, but no so great to allow wiring, for instance between the sensor and housing, to become tangled within the housing. Alternatively, a pivoting stop bracket and with stops may be mounted on the exterior of the housing and interface with a projecting finger such as finger 50.1 (the position of the finger and stop bracket may be interchanged), however, this is not preferred as the pivoting bracket is exposed to the external environment and may be damaged.

As shown in FIG. 4A, the inner sidewall of the compartment 10 contain detents or notches 55 located at various positions on the sidewall. Their functionality will be described later. Additionally inner sidewall has threads 54 to accommodate a cover. Threads could be on the outer sidewall, or another means of removably covering the opening into the compartment 10 could be used.

Shown in FIGS. 5A & B is module holder 40. As shown, holder 40 is an “U” shaped arm. Located on the bottom of the arm are shown two inserts 42 (a single insert can be employed) to retain an electrical plug, connector or socket, and a hollow cylinder mount 43. Additionally, coaxial cable connectors can be included in the arm. Module holder 40 is rotatably mounted in the chamber 10 by sliding cylinder mount 43 onto cylinder 14, and may be secured to cylinder via screw (threaded into cylinder 14), a snap ring, or other retaining device. It is preferred that the module holder 40 be raised from the floor of the compartment 10 to accommodate wiring to be positioned between the rotatable module holder 40 and the floor of the compartment 10, later described. For this reason, the cylinder 14 may be a “stepped cylinder” such as shown in detail 4C. Each upstanding arm of the “U” shaped module holder 40 includes an outward facing finger or bump 44, located on the arms at a height to fit into the notches 55 in the inner wall of the compartment 10 (a single arm may be so equipped, but it is preferred to use two arms, both so equipped). The arms are somewhat flexible, allowing the notches 55 and projecting fingers act as a “click stop” or detent mechanism to fix the location of the rotatable module holder 40 with respect to the housing. The inward facing surface of the upstanding arms contains a projecting finger or bump 47, designed to interface a similarly positioned notch or depression in the module to retain the module in the module holder 40 in a click-lock arrangement. Obviously, the bumps and notches could be interchanged and accomplish the same result. Instead of bumps on the inner walls of the module holder's arms, the top of the module holder's arms may have inward projecting flanges designed to retain a module, next described. An alternative design is to have an outwardly projecting tab or ear at the top of each arm of the U shaped module holder (or only on one arm) (not shown). These tabs would ride on a ledge formed in the sidewall of the module compartment. The click stop arrangement of bumps and notches could be employed in the tab/ledge relationship, or alternatively, the ledge may have cutouts sized to accommodate the tab portion, so that as the tab rotates, it would fall into a corresponding cutout to lock the position of the module holder in the module compartment. All of these arrangements are considered a means to engage the module holder with the module compartment. The module holder may also comprise an “L” shaped holder, having only a single upstanding arm.

Positioned onto module holder 40 is a electronic module 60 (see FIG. 6). As shown in FIGS. 6A and 6B, module includes a top 66, and a base, 67, and an electronics package that slides into the cover (not show). Module 60 will contain the electrical components to allow a user to interact with the sensor, and allow the sensor to interact with the module. The particular module 60 shown is designed to interface a level sensor, and contains a screen or alpha numeric display to display the sensors return signal. For this reason, module top 66 has a viewing window 61, and interface buttons 62 to manually interact with the electronics in the module 60, and plugs 62.1 to allow a user to interact via another plug-in instrument. Located on the bottom of the module (FIG. 6B) are one or two electrical connectors or sockets 65 (such as a male adapter) designed to interface a corresponding connector (such as a female adapter) positioned in the insert 42 on the module holder 40. Two connectors are preferred, one to connect the module 60 with the sensor wiring, the other to connect the module 60 to the wiring from the terminal compartment. When the module 60 is positioned in the module holder 40, the module 40 will snap into place in the holder 40, aligning the plugs or pins 65 in the module 60 with plugs or pins positioned in the inserts 42 in the module holder 40. Other arrangements of, or multiple connectors, may be used to fit the particular needs of the level sensor. This includes separate connectors for wireless antennas or a special communications link, for example.

As shown in FIG. 6A, the module 60 has two lengthwise slots 69 to accommodate the arms of the module holder 40. Slots have notches 69.1 to accommodate the fingers or bumps on the module holder's arms. Also shown are two lengthwise channels 68. Sliding in each of these channels is a module puller 90 (see FIG. 6C). Module pullers 90 have a projecting stop 92 that will retain the bar 90 in the channel 68, preventing upward removal of the bar. Module pullers 90 are use to assist removal of a module 60 installed in the module holder 40, when positioned in the compartment 10. To remove a module 60, the module pullers 90 are slid upwardly until the stop 92 catches on the module cover 66. Further upward force on the module pullers 90 will overcome the click stop frictional arrangement between the module holder's arms and compartment sidewalls, allowing removal of the module from the module holder. The module pullers 90 provide a grasping surface, and other mechanical means can be used, such as a grasp hook pivotably mounted to the module holder case, finger grip ridges molded in the module case, etc.

It is preferred that the fit between the module holder 40, the module 60, and compartment 10 chamber be close, so that the insertion of the module 60 into the holder 40 will force the fingers or bumps 44 of the holder's arms into the notches 55 in the compartment wall, thereby fixing the position of the interlocked module 60 and module holder 40 with respect to the compartment 10. Further rotation of the module/holder is thus prevented. In this arrangement, the module holder, module and housing are locked into a desired position, and any change of this relationship requires removal of the module 60 from the holder 40.

FIG. 7 is a cross section through the housing showing the relationship of the assembled parts. A cover 70 is then put over the opening in the compartment 10, thus enclosing the components therein. If an explosion proof arrangement is not needed, the cover may simply be a retaining ring threaded or snapped onto or into the top of the compartment 30 opening, thus allowing the user to view and interact with the module.

The module holder as described is locked into a desired orientation by the click stop or detent relationship between the module holder 40 and inner sidewalls of the compartment 10. Other mechanical means may be used to accomplish this task. For instance, the module top 66 may have a ridges that snap into channels in the sidewall of the compartment 10 (or vice versa) in an interlocking arrangement, such as a dovetail-type joint. These channels in the sidewall may be placed at various locations on the sidewall, for instance, at 15 degree intervals, to permit the module to snap in place at various orientations (0 degrees, 15 degrees, 30 degrees, etc.). In this arrangement, the module holder 40 may be dispensed with. A sufficient length wiring harness (attached to the module or the compartment) may be employed to electrically connect the module and compartment wiring, and allow the module to be removed form the compartment before disconnecting the wiring. For instance, the module may incorporate one or two plugs that connect with matching plugs or blocks in the housing, with a sufficient length of cable attached to the plugs to allow the module to be removed, and then unplugged. Alternatively, each ridge in the module cover may include a plug that snaps into place in a matching plug located in the corresponding sidewall channel (each channel preferably having such a plug to allow for different orientations of the module in the compartment). Alternatively, the module may have a series of pins positioned on the module bottom, where each pin is positioned to touch one of a series of annular conductors mounted on a fixed plate (e.g. a flat slip ring disk) in the compartment bottom (of vice versa, e.g., the bottom of the module cover has positioned a series of annular conductors, etc). Alternatively, other slip ring or commentator arrangements may be employed between the module and a module holder. The above embodiments provide the ability to position the module at a selected orientations within the module compartment. The cooperation of the module with module compartment, or the module holder with the module compartment, provides a means to fix the position of the module in the module compartment at a select one of several positions. This “means” thus allow the user to set and fix the position of the module in the module compartment at a desired orientation.

Compartment 30 may be closed by a blank cover since this compartment does not typically provide any display for the user. For an explosion proof housing, it is preferred that cover for compartment 10 include a glass window to provide a view port in the cover 70. A preferred window cover is shown in cross section in FIGS. 8A, B, and C. Cover 70 includes an annular ring 71, with an opening therethrough. The ring is threaded, and has a top rim 75 to retain a glass insert 72. Positioned between top rim surface and glass 72 is an “O” ring 73. “O” ring 73 is retained in a circular channel cut in the underside of the ring 71 top. The inside sidewall of the ring 71 also has a grooves 78.1 into the side wall to accommodate the flats 77.1 of the locking ring 77 (next described). A channel(s) in the sidewall 76 enters the bottom portion of the grooves. The channel 76 may be circumferential, or each groove 78.1 will have an associated short channel 76 exiting the bottom of the groove 78.1 to accommodate the flats 77.1 of the locking ring in a locked position.

Locking ring 77 may be similar to an open snap ring, or be a closed circular ring 77. The locking ring 77 depicted in FIG. 8B is a closed ring and includes projecting flats 77.1, and cutouts 77.2. To install, the locking ring flats 77.1 are aligned with the corresponding grooves 78.1, the locking ring 77 is slid down the interior sidewall 78 of the outer ring 70 until the locking ring is even with channel 76, and then the locking ring is rotated, placing the ring flats 77.1 in the channel 76 or short channels 76, thereby by retaining the locking ring 77 in ring 71. The locking ring's outer diameter is smaller then the inner diameter of the ring 71, leaving a gap 79 between the locking ring 77 and inner sidewall 78 of the ring 71. After the cover 70 is assembled, epoxy 80 may be easily inserted (such as by a syringe though this gap 79) between the glass 72, the inner sidewall 78, and the top rim 75. This epoxied fit is needed to comply with standards set by the International Electrotechnical Commission (IEC) for explosion proof standards, particularly IEC 60079-1, hereby incorporated by reference. The cutouts 77.2 are used to manipulate an installed ring. Projecting flats 77.1 may be inclined at a slight angle with respect to the locking ring 77 to help retain an installed ring in the channel.

The cover may have internal threads or external threads to intermate with suitably positioned threads on the housing. The threadable join is needed for explosion proof housings, but other means of attaching a cover, know to those of skill in the art, may be used in a non-explosion proof embodiment. The locking ring shown is a completely closed ring, however, the locking ring may be a snap ring with projecting flats. If a snap ring is used as a locking ring, the grooves 78.1 in the sidewall may be dispensed with, as the locking ring can be compressed to allow the projecting flats 77.1 to clear the sidewall 78 when installing. Alternatively, the channel 76 may be dispensed with and the grooves 78.1 retained, in which event the snap ring should have sufficient expansive force, when installed, to force the flats in a tight relationship in the grooves 76 to retain the snap ring.

Another embodiment includes a two piece snap ring comprising two co-planar inner and outer rings, offset from each other by a gap, and joined together at discrete intervals. The outer ring is sized to be insertable into the channel 76 in the sidewall 78 of the cover, and the inner ring is sufficiently offset from the outer ring so that the gap between the inner/outer rings is adjacent the sidewall of the cover, thereby providing the needed space for injection of epoxy adjacent the glass. With this dual ring embodiment, the projecting flanges are not needed. The interior of the terminal compartment 30 is detailed in FIG. 9. Two ports 23 allow access to the interior of this compartment, while channel 21 allows wiring to be passed from this compartment to the module compartment. As shown, this compartment has a raised flat flange 32, on which a semicircular terminal block, circuit board or wafer board may be attached. Wiring (such as for power and communications) is brought into the terminal compartment through ports 23 (generally through a single port). One of the ports may be used for a mounting an antenna to allow for wireless communications. Wiring from the board (or from the outside through port 23) travels into the module compartment via port 21 to provide power/communications to the electronic module in the module compartment. Generally, once the wiring is in place between the two compartments, the port 21 will be filled with sealant or epoxy to environmentally isolate the two compartments. In a single compartment design, (i.e. no terminal compartment), wiring (such as power) would be brought directly into the module compartment, either through port 22, of via a port positioned as needed into the module compartment.

Because the module may rotate slightly over 360 degrees, it is necessary to accommodate the internal wiring in the module compartment 20 to allow for rotation of the module. Shown in FIG. 10 is the module compartment 10, with center cylinder 14. The module holder 44 is shown dashed. Also shown are the inserts 42 on the module holder into which the electrical connectors are positioned. The wiring 100 connects to the electrical connectors in the inserts 42. Wiring 100 is preferably a ribbon type cable with sufficient length within the chamber to accommodate the movement of the electrical connector in the links 42. A round cable or cable bundle may also be employed, and posts in the floor of the module compartment may be used to guide cable movement. For an explosion proof housing, the cover 70 should include the sealing features disclosed the provisional application entitled “Explosion Proof Housing Cover Seal” application No. 61/122,958 filed on Dec. 16, 2008 (hereby incorporated by reference). 

1. A housing comprising a housing body having an exterior surface and an interior defining a module compartment, said module compartment having a sidewall, a bottom, and an open top; a cover for said open top of said module compartment; an electronic module positioned in said module compartment; a first port in said housing, said first port connecting said module compartment to the exterior surface of said housing; a sensor connector connected to said housing body at said first port; a sensor connected to said sensor connector; said module operationally connected to said sensor; said housing having a means to allow said sensor connector to rotate about said housing body within a predetermined fixed range.
 2. The housing in claim 1 wherein said fixed range is about 360 degrees.
 3. A housing comprising a housing body having an exterior surface and an interior defining a module compartment, said module compartment having a sidewall, a bottom, and an open top; a cover for said open top of said module compartment; an electronic module positioned in said module compartment, a first port in said housing, said first port connecting said module compartment to the exterior surface of said housing, a sensor connector connected to said housing body at said first port, a sensor connected to said sensor connector, said module operationally connected to said sensor; said housing having a means to fix the position of the module in the module compartment at a selected one of several positions.
 4. A housing comprising a housing body having an exterior surface and an interior defining a module compartment, said module compartment having a sidewall, a bottom, and an open top; a cover for said open top of said module compartment; an electronic module positioned in said module compartment, a first port in said housing, said first port connecting said module compartment to the exterior surface of said housing, a sensor connector connected to said housing body at said first port, a sensor operationally connected to said sensor connector, said module operationally connected to said sensor; said module fixedly engagable with said module compartment at a selected discrete number of positions.
 5. The housing compartment in claim 3 further having a module holder rotatably mounted in said module compartment, said module mounted in said module holder, said module holder and said module compartment cooperating to fixedly engage said module compartment at a selected finite number of positions.
 6. A housing comprising a housing body having an exterior surface and an interior defining a module compartment, said module compartment having a sidewall, a bottom, and an open top; a cover for said open top of said module compartment; an electronic module positioned in said module compartment; a first port in said housing, said first port connecting said module compartment to the exterior surface of said housing; a sensor connector connected to said housing body at said first port; a sensor connected to said sensor connector; said module operationally connected to said sensor; said housing rotatable about said sensor connector in a fixed range.
 7. A cover for a explosion proof housing body opening, said cover comprising an annular threaded ring, said threaded ring having an opening therethrough and a top rim around said opening, and an interior surface; said cover including an locking ring having an outer periphery portion, said outer periphery portion engaging said interior surface of said threaded ring whereby said engaged locking ring forms a gap substantially between the circumference of said inner surface of said cover and said locking ring; a glass portion sized to fit in said interior surface of said threaded ring and retained by said rim; said glass portion positioned between said rim and said locking ring, and said locking ring adapted to retain said glass adjacent said rim. 